Lubricant for metal forming process



LUERIQANT FOR METAL FOG PRGCESS Arthur M. Shapiro, Philadeiphia, Pa.,assignor to the United States of America as represented by the Secretaryof the Army No Drawing. Filed Nov. 30, 1960, Ser. No. 72,309

3 Claims. (Cl. 29-523) (Granted under Title 35, US. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes without the payment to meof any royalty thereon.

This application is a continuation-in-part of my application Serial No.4,825, filed January 26, 1960, entitled Lubricant for Metal FormingProcess, now abandoned.

This invention relates to metal forming lubricants. Its purpose is toprovide an improved lubricant whereby the force of the metal shapingoperation, such as cold drawing and stamping, is materially reduced.

Heretofore various aqueous soap solutions have been utilized in theformation of metal objects. These solutions have generally includedsodium soaps which contain a plurality of fatty acids. As a result ofcomparative tests, it has been found that certain sodium soapscontaining a single acid will function to reduce the required metalforming force to an extent not realized with sodium soaps containing aplurality of fatty acids.

The results of these tests are shown in the following tabulation. Thefirst column of this tabulation lists a series of single acid sodiumsoaps. The second column indicates the number of carbon atoms in thefatty acid while the third column shows the number of double bonds inthe acid. The fourth column indicates the percent difference in theforces required to cold draw a 70-30 lbrass draw piece into a 30 calibercartridge casing using typical commercially available multiple fattyacid soaps containing between about 20 to 40% sodium oleate and about 60to 80% sodium stearate and the sodium soaps of my invention. The minussigns in column 4 indicate that the single acid soaps of the inventionrequired less force to form the cartridge case than when multiple acidsoaps were employed. The positive signs indicate the opposite. The lastcolumn presents data similar to those of column 4, but with a mild steelsuch as 1020.

The percentages above represent averages of five individual runs. Themultiple fatty acid soaps used to obtain the comparison data above,i.e., the 20-40% sodium oleate and 60-80% sodium stearate, wereconsidered the 3,098,294 Patented July 23, 1963 most satisfactory todate as revealed by exhaustive laboratory experimentation with colddrawing -30 and -20 brass and mild steels. Other multiple fatty acidsoaps containing a mixture of ingredients such as lard oil, soy beanoil, and tallow fatty acid soaps (40 titre) yielded results inferior tothe multiple fatty acid soaps used. The data above are alsorepresentative of those obtained when cold drawing 50 caliber 70-30brass, and 30 and 50 caliber mild steel, into cartridge casings.

In utilizing sodium behenate soap as a lubricant in cold drawingoperations, the metal is cleaned if required and immersed in a 1 to 2%solution of sodium behenate in water which is maintained at atemperature of about F. to 200 F. for about 3 to 5 minutes. Thereafter,one of several procedures is followed. According to one procedure, themetal is removed from the solution and immediately cold drawn whileflooding it with the heated solution. Another procedure involvesremoving the metal from the heated solution and allowing it to dry overnight, and then dipping it in the heated solution before cold drawing.Still another procedure is to remove the metal from the heated solution,dry over night, and cold draw in that condition. The tabulated data wereobtained using the second procedure outlined above, but generallycomparable data were obtained when using any of the three methodsoutlined above.

For larger caliber cases or heavier gauge metals, the sodium behenatemay be increased upwardly to about 20% of the aqueous solution.

As will be understood by those skilled in the art, the improvedlubrication made possible by the present invention has the importantadvantage that it decreases power consumption, prolongs the life of thedies used, and permits the forming of heavier gauge metal.

-I claim:

1. In a process of cold drawing a small article from a draw piece madeof a metal selected from the group consisting of 70-30 brass, 80-20brass, and mild steel, the steps comprising immersing the metal to becold drawn in an aqueous solution of about 1 to 2% sodium behenate soap,said solution being maintained at a temperature between about 150 to 200F., permitting said immersed metal to remain submerged in said heatedsolution for a period ranging between about 3 to 5 minutes, removingsaid immersed metal from the heated solution and cold drawing saidremoved metal into a small article while flooding with said heatedsolution.

2. In a process of cold drawing a small cartridge case from a draw piecemade of a metal selected from the group consisting of 70-30 brass, 80-20brass, and mild steel, the steps comprising immersing the metal to becold drawn in an aqueous solution of about 1 to 2% sodium behenate soap,said solution being maintained at a temperature between about 150 to 200F., permitting said immersed metal to remain submerged in said heatedsolution for a period ranging between about 3 to 5 minutes, removingsaid immersed metal from the heated solution, allowing said removedmetal to dry over night and cold drawing said dried metal into a smallcaliber cartridge case.

3. In a process of cold drawing a small cartridge case from a draw piecemade of a metal selected from the group consisting of 70-30 brass, 80-20brass, and mild steel, the steps comprising immersing the metal to becold drawn in an aqueous solution of about 1 to 2% sodium behenate soap,said solution being maintained at a temperature between about 150 to 200F., permitting said immersed metal to remain submerged in said heatedsolution for a period ranging between about 3 to 5 minutes, removingsaid immersed metal from the heated solution, allowing said removedmetal to dry over night, dipping said removed metal into said heatedsolution and immediately cold drawing said dipped metal into a smallcartridge case.

UNITED STATES PATENTS Salender Apr. 13, 1937 Spring Sept. 21, 1943Whitney Oct. 14, 1952 Leduc Jan. 27, 1959 Fucinari Dec. 27, 1960

1. IN A PROCESS OF COLD DRAWING A SMALL ARTICLE FROM A DRAW PIECE MADEOF A METAL SELECTED FROM THE GROUP CONSISTING OF 70-30 BRASS, 80-20BRASS, AND MILD STEEL, THE STEPS COMPRISING IMMERSING THE METAL TO BECOLD DRAWN IN AN AQUEOUS SOLUTION OF ABOUT 1 TO 2% SODIUM BEHENATE SOAP,SAID SOLUTION BEING MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 150 TO200*F., PERMITTING SAID IMMERSED METAL TO REMAIN SUBMERGED IN SAIDHEATED SOLUTION FOR A PERIOD RANGING BETWEEN ABOUT 3 TO 5 MINUTES,REMOVING SAID IMMERSED METAL FROM THE HEATED SOLUTION AND COLD DRAWINGSAID REMOVED METAL INTO A SMALL ARTICLE WHILE FLOODING WITH SAID HEATEDSOLUTION.